title: Altered adherence properties of a Streptococcus gordonii hppA (oligopeptide permease) mutant result from transcriptional effects on cshA adhesin gene expression.
abstract: Cell-surface polypeptide CshA (259 kDa) mediates multiple adherence interactions of Streptococcus gordonii. By generating a chromosomal cshA promoter (p-cshA)-cat gene fusion and measuring both CAT enzyme activity and cat mRNA levels, it was shown that cshA is expressed maximally in cells in the late exponential phase of growth in batch culture. The expression of CAT enzyme activity from the p-cshA-cat promoter fusion was 28% decreased in early stationary phase cell extracts of mutant strain OB528 in which the hppA (oligopeptide-binding lipoprotein) gene was insertionally inactivated. This effect was correlated with proportionally reduced cell-surface expression of CshA protein and with impaired adherence of hppA mutant cells to cells of an oral Actinomyces naeslundii strain. cshA promoter activity was enhanced in streptococcal cells that were incubated in conditioned culture medium as opposed to fresh medium, but this did not occur in an hppA genetic background. It is suggested that HppA is necessary for the response of cells to an extracellular factor that modulates cshA transcription, and hence affects cell-surface CshA expression and streptococcal cell adherence properties.
authors.affiliation: Molecular Oral Biology Laboratory, Department of Oral Biology and Oral Pathology, University of Otago, PO Box 647, Dunedin, New Zealand.
authors.forename: Roderick
authors.initials: R
authors.lastname: McNab
authors.affiliation: Molecular Oral Biology Laboratory, Department of Oral Biology and Oral Pathology, University of Otago, PO Box 647, Dunedin, New Zealand.
authors.forename: Howard F
authors.initials: HF
authors.lastname: Jenkinson
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism; D001422:Bacterial Adhesion / Q000235:genetics*; D001426:Bacterial Proteins / Q000096:biosynthesis*; D001483:Base Sequence; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism*; D015500:Chloramphenicol O-Acetyltransferase; D003001:Cloning, Molecular; D015964:Gene Expression Regulation, Bacterial; D005838:Genotype; D007700:Kinetics; D008074:Lipoproteins / Q000235:genetics* / Q000378:metabolism*; D008565:Membrane Proteins; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism*; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D013291:Streptococcus / Q000235:genetics / Q000502:physiology*; D014158:Transcription, Genetic
chemical_list: D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D002352:Carrier Proteins; C079041:CshA protein, Streptococcus gordonii; C097616:HppA protein, Streptococcus gordonii; D008074:Lipoproteins; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; D011993:Recombinant Fusion Proteins; C037230:oligopeptide permease, Bacteria; D015500:Chloramphenicol O-Acetyltransferase